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Numbers whose base-9 representation has the same nonzero number of 3's and 8's.
1

%I #17 Jun 12 2024 12:44:58

%S 35,75,116,156,197,237,251,260,269,287,296,305,314,315,316,317,319,

%T 320,321,322,359,399,440,480,521,561,602,642,651,660,669,675,676,677,

%U 679,680,681,682,687,696,705,714,764,804,845,885,926,966,980,989,998

%N Numbers whose base-9 representation has the same nonzero number of 3's and 8's.

%H Iain Fox, <a href="/A039382/b039382.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[1000],DigitCount[#,9,3]==DigitCount[#,9,8]>0&] (* _Harvey P. Dale_, Jun 12 2024 *)

%o (PARI) is(n) = { my(d = digits(n, 9), i = 0, j = 0); for(x=1, length(d), if(d[x] == 3, i++, if(d[x] == 8, j++))); return(i==j && i!=0); } \\ _Iain Fox_, Nov 21 2017

%Y Cf. A007095.

%K nonn,base,easy

%O 1,1

%A _Olivier GĂ©rard_